The safety valve widely used in petrochemical production units is the ( ) safety valve.

When selecting a pressure gauge, the measuring range of the pressure gauge is generally the highest working pressure of the pressure vessel ( ).

Before the vacuum pressure gauge is installed, check that the gauge pointer is in the ( ) position.

According to the regulations, the accuracy of pressure gauge installed in containers above medium pressure should be ( ) level.

Vacuum pressure gauge can be measured directly ( ).

The main function of the copper wire mesh inside the flame arrester is ( ).

A flame arrester is a safety unit used to prevent the spread of flame and ( ) explosion of flammable gases and flammable liquid vapors.

A flame arrester is a ( ) unit.

When a blockage occurs on the flame arrester, it should ( ).

The verification period of the strong pressure gauge is generally ( ).

What is wrong with the following statement about pressure gauge replacement is ( ).

If the pressure gauge is suspected of failure, the most reliable way is ( ), you can determine whether the pressure gauge has failed.

Before replacing the gauge, check that the gauge pointer is in the ( ) position.

The following precautions for replacing a pressure gauge when normal production is correct are ( ).

The accuracy of pressure gauge installed according to the specified low pressure vessel should be ( ) class.